The goal of this clinical trial is to learn whether self-administered auricular acupressure integrated with a smartphone application works to reduce weight in patients with obesity accompanied with obesity-related comorbid illness. The main questions it aims to answer are:

• Is there significant difference in the Body Mass Index (BMI) between the self-administered auricular acupressure integrated with a smartphone app (Version 2) group (experimental group) and the usual care group, in people with obesity accompanied with metabolic syndrome?
• Are there significant differences in other anthropometric parameters between the two groups? These parameters include waist circumference, body fat percentage, skeletal muscle percentage, and waist-to-hip ratio.
• Are there any significant differences in obesity-related parameters between the two groups? These parameters include blood lipid profile (triglyceride, total cholesterol, low-density lipoprotein (LDL), and high-density lipoprotein (HDL)), blood glucose concentrations (fasting glucose and glycated haemoglobin/ HbA1c), and blood pressure.

Participants in the experimental group will:

• Be affixed with 6 to 8 hypoallergic Vaccariae Semen ear patches on one ear each time
• Visit the clinic twice a week to change a new set of ear patches on the opposite ear
• Will undergo this intervention for 8 weeks
• Install a smartphone application which will send pop-up notifications to remind them to press on the ear patches regularly every day
• Keep a record on the number of times pressing on the smartphone application

Obesity has become a global public health problem, and its prevalence is surging in Asia. According to the Population Health Survey in 2020-22 by the Department of Health in Hong Kong, over 50% of Hong Kong general population was classified as obese (Body Mass Index (BMI) ≥ 25.0 kg/m2) or overweight (BMI ≥ 23.0 kg/m2), and central obesity was accounting for 37.8%. As the population ages, overweight and obesity become more and more serious. The incidence of metabolic syndrome is increasing yearly around the world. According to the health survey mentioned above, the prevalence of various disorders that constitute metabolic syndrome ranged from 8.5% (hyperglycaemia or diabetes) to 51.9% (raised blood cholesterol or hypercholesterolaemia). Metabolic syndrome is a collective disorder comprising abdominal obesity, abnormal blood sugar, dyslipidaemia and hypertension, which seriously affects the health of the body and cannot be ignored.

Western medications currently used for weight reduction include centrally-acting appetite suppressants, blockers inhibiting intestinal fat absorption, and metabolic stimulants. Although these Western medications are effective in treating obesity, the associated adverse effects limit their clinical applications. Long-term use of weight reduction medications can cause many adverse effects in the cardiovascular system, digestive system, and liver. Bariatric surgery, such as gastric bypass or sleeve gastrectomy, may cause serious complications, for instance, bleeding, intestinal obstruction, anorexia, or gastric perforation.

In recent years, mobile health (mHealth) has played an essential role in preventing and managing chronic diseases. In the fields of both medicine and nursing care, smartphone apps are widely used to assist in the intervention of chronic diseases. A smartphone app can remind participants to press the ear patches promptly and correctly to achieve optimum treatment effect. In addition, the smartphone app can also provide relevant health information to encourage people with obesity to change their unhealthy lifestyles.

Through literature review and expert consultation, the research team selected six auricular acupoints that were found to have specific effects on weight reduction, namely Shenmen, Stomach, Endocrine, External nose (also known as "hunger point"), Large intestine, and Forehead. Not only does the smartphone app remind the participants to press on the auricular acupoints, the participants can also learn about the benefits of auricular acupressure, the locations of auricular acupoints, and the correct way of executing auricular acupressure on the smartphone app.

This proposed research project aims to evaluate the efficacy of self-administered auricular acupressure integrated with a smartphone app (Version 2), a composite intervention for people with obesity accompanied with metabolic syndrome. It will be a two-arm randomised clinical trial conducted in a community setting.

Inclusion Criteria:

1. age ≥ 18 years;
2. Body Mass Index (BMI) ≥ 30 kg/m2 and /or abdominal obesity (i.e., central obesity), that is, male waist circumference ≥ 90cm while female waist circumference ≥ 80cm;
3. fulfils diagnostic criteria for metabolic syndrome with any two or more of the following: (a) blood pressure ≥ 130/85 mmHg and/ or confirmed diagnosis of hypertension with treatment; (b) fasting blood glucose ≥ 100 mg/dl (5.6 mmol/L) and/ or confirmed diagnosis of diabetes with treatment; (c) fasting triglyceride ≥ 150 mg/dl (1.7 mmol/L) and/ or received specific treatment on dyslipidaemia; (d) fasting high-density lipoprotein (HDL) < 40mg/dl (< 1.03mmol/L) in male; < 50mg/dl (< 1.29 mmol/L) and/ or received specific treatment on dyslipidaemia; These standards are based on the diagnostic criteria for metabolic syndrome from the World Health Organisation (1999), the International Diabetes Federation Criteria (2005), and the Chinese Diabetes Society (2000);
4. are taking medications and receiving follow-up medical consultation [Note: With the consent of the participants, the researchers (i.e., the RCA and the RA) will verify relevant medical records in the follow-up appointments];
5. taken no weight control measures in the past 6 months;
6. has no trauma, inflammation or pathological lesion on ears;
7. is a smartphone user.

Exclusion Criteria:

1. has any eating disorder (screened by the 5-item SCOFF questionnaire);

2. has drug-induced obesity;

3. is pregnant;

4. has cognitive impairment (Abbreviated Mental Test (Hong Kong version), AMT score below 6 (less than or equal to 5) will be excluded.);

5. has cancer; or

6. has a severe body disability, such as hemiplegia, that may prevent following instructions to use the smartphone.

7. is planning to have weight-reduction treatment(s) (such as medications targeted for weight reduction, and bariatric surgery) in the coming 6 months.

8. is taking the following medications that potentially affect the body weight:

   • Corticosteroids (e.g., prednisone and dexamethasone)
   • Second generation antipsychotics (e.g., olanzapine, clozapine, quetiapine and risperidone)
   • Levothyroxine
   • FDA-approved medications for obesity or weight loss (e.g., phentermine, diethylpropion, phendimetrazine, phentermine + topiramate extended release (ER), naltrexone + bupropion ER, orlistat, liraglutide, semaglutide and GLP-1 (liraglutide/ semaglutide) + tirzepatide)